Transgenic rabbits with increased VEGF expression develop hemangiomas in the liver: a new model for Kasabach-Merritt syndrome

Infantile hemangioma models: is the needle in a haystack?

Infantile hemangioma (IH) is the most prevalent benign vascular tumor in infants, with distinct disease stages and durations. Despite the fact that the majority of IHs can regress spontaneously, a small percentage can cause disfigurement or even be fatal. The mechanisms underlying the development of IH have not been fully elucidated. Establishing stable and reliable IH models provides a standardized experimental platform for elucidating its pathogenesis, thereby facilitating the development of new drugs and the identification of effective treatments. Common IH models include the cell suspension implantation model, the viral gene transfer model, the tissue block transplantation model, and the most recent three-dimensional (3D) microtumor model. This article summarizes the research progress and clinical utility of various IH models, as well as the benefits and drawbacks of each. Researchers should select distinct IH models based on their individual research objectives to achieve their anticipated experimental objectives, thereby increasing the clinical relevance of their findings.

Rapamycin induces autophagy and apoptosis in Kaposiform hemangioendothelioma primary cells in vitro

BACKGROUND

Rapamycin has been recommended to treat Kaposiform hemangioendothelioma (KHE) with Kasabach-Merritt phenomenon (KMP), but the underlying mechanism of the clinical effect has not been established. Therefore, we determined rapamycin cytotoxicity on KHE cells in vitro and the underlying mechanism.

METHODS

KHE primary cells were derived from a tumor specimen and treated with rapamycin. Immunofluorescence was applied to identify the cells. Cell viability was measured using the Cell Counting Kit-8 (CCK-8) assay. Cell cycle and apoptosis were assessed using flow cytometry (FCM). Western blots (WB) were performed to determine phosphorylation of mammalian target of rapamycin (mTOR), p70 S6 kinase (S6K1), and eukaryotic translation initiation factor 4E-binding protein 1 (4E-BP1), as well light chain 3 (LC3) expression.

RESULTS

Rapamycin inhibited the growth of KHE primary cells in a dose- and time-dependent manner. Cell cycle progression was arrested in the G0/G1 phase and apoptosis was induced. WB results showed that LC3-II/I expression was significantly elevated in KHE primary cells treated with rapamycin, while the level of p-mTOR, p-S6K1, and p-4E-BP1 expression was reduced. LC3 fluorescent spots were increased in the rapamycin treatment group.

CONCLUSIONS

Rapamycin inhibited KHE primary cell proliferation, induced apoptosis and autophagy, and blocked the mTOR signaling pathway.

Genetically modified rabbit models for cardiovascular medicine

Genetically modified (GM) rabbits are outstanding animal models for studying human genetic and acquired diseases. As such, GM rabbits that express human genes have been extensively used as models of cardiovascular disease. Rabbits are genetically modified via prokaryotic microinjection. Through this process, genes are randomly integrated into the rabbit genome. Moreover, gene targeting in embryonic stem (ES) cells is a powerful tool for understanding gene function. However, rabbits lack stable ES cell lines. Therefore, ES-dependent gene targeting is not possible in rabbits. Nevertheless, the RNA interference technique is rapidly becoming a useful experimental tool that enables researchers to knock down specific gene expression, which leads to the genetic modification of rabbits. Recently, with the emergence of new genetic technology, such as zinc-finger nucleases (ZFNs), transcription activator-like effector nucleases (TALENs), clustered regularly interspaced short palindromic repeats (CRISPR), and CRISPR-associated protein 9 (CRISPR/Cas9), major breakthroughs have been made in rabbit gene targeting. Using these novel genetic techniques, researchers have successfully modified knockout (KO) rabbit models. In this paper, we aimed to review the recent advances in GM technology in rabbits and highlight their application as models for cardiovascular medicine.

Fibrin-based factor delivery for therapeutic angiogenesis: friend or foe?

Therapeutic angiogenesis aims at promoting the growth of blood vessels to restore perfusion in ischemic tissues or aid tissue regeneration. Vascular endothelial growth factor (VEGF) is the master regulator of angiogenesis in development, repair, and disease. However, exploiting VEGF for therapeutic purposes has been challenging and needs to take into account some key aspects of VEGF biology. In particular, the spatial localization of angiogenic signals within the extracellular matrix is crucial for physiological assembly and function of new blood vessels. Fibrin is the provisional matrix that is universally deposited immediately after injury and supports the initial steps of tissue regeneration. It provides therefore several ideal features as a substrate to promote therapeutic vascularization, especially through its ability to present growth factors in their physiological matrix-bound state and to modulate their availability for signaling. Here, we provide an overview of fibrin uses as a tissue-engineering scaffold material and as a tunable platform to finely control dose and duration of delivery of recombinant factors in therapeutic angiogenesis. However, in some cases, fibrin has also been associated with undesirable outcomes, namely the promotion of fibrosis and scar formation that actually prevent physiological tissue regeneration. Understanding the mechanisms that tip the balance between the pro- and anti-regenerative functions of fibrin will be the key to fully exploit its therapeutic potential.

Genetically Modified Rabbits for Cardiovascular Research

Rabbits are one of the most used experimental animals for investigating the mechanisms of human cardiovascular disease and lipid metabolism because they are phylogenetically closer to human than rodents (mice and rats). Cholesterol-fed wild-type rabbits were first used to study human atherosclerosis more than 100 years ago and are still playing an important role in cardiovascular research. Furthermore, transgenic rabbits generated by pronuclear microinjection provided another means to investigate many gene functions associated with human disease. Because of the lack of both rabbit embryonic stem cells and the genome information, for a long time, it has been a dream for scientists to obtain knockout rabbits generated by homologous recombination-based genomic manipulation as in mice. This obstacle has greatly hampered using genetically modified rabbits to disclose the molecular mechanisms of many human diseases. The advent of genome editing technologies has dramatically extended the applications of experimental animals including rabbits. In this review, we will update genetically modified rabbits, including transgenic, knock-out, and knock-in rabbits during the past decades regarding their use in cardiovascular research and point out the perspectives in future.

Transgenic Rabbit Models: Now and the Future

Transgenic rabbits have contributed to the progress of biomedical science as human disease models because of their unique features, such as the lipid metabolism system similar to humans and medium body size that facilitates handling and experimental manipulation. In fact, many useful transgenic rabbits have been generated and used in research fields such as lipid metabolism and atherosclerosis, cardiac failure, immunology, and oncogenesis. However, there have been long-term problems, namely that the transgenic efficiency when using pronuclear microinjection is low compared with transgenic mice and production of knockout rabbits is impossible owing to the lack of embryonic stem cells for gene targeting in rabbits. Despite these limitations, the emergence of novel genome editing technology has changed the production of genetically modified animals including the rabbit. We are finally able to produce both transgenic and knockout rabbit models to analyze gain- and loss-of-functions of specific genes. It is expected that the use of genetically modified rabbits will extend to various research fields. In this review, we describe the unique features of rabbits as laboratory animals, the current status of their development and use, and future perspectives of transgenic rabbit models for human diseases.

Isolated hepatic hemangiomatosis in 2 septuagenarians

We report 2 cases of isolated hepatic hemangiomatosis: a 76-year-old woman who is, to our knowledge, the oldest person with this diagnosis, and a 74-year-old woman. Magnetic resonance imaging of the abdomen showed T2 hyper intense lesions throughout the liver, peripheral nodular arterial enhancement, and filling of contrast on the portal venous and delayed phases. Computed tomography showed liver lesions with peripheral nodular enhancement in the early phase and a centripetal pattern or "filling in" during the late phase; the lesions opacified after a delay of 3 or more minutes and remained isodense or hyperdense on delayed scans. Both images were consistent with hepatic hemangiomatosis. These cases help increase awareness about benign and unusual liver lesions with radiologic characteristics similar to those of malignant liver tumors. The authors also present a review of 15 other cases of isolated hepatic hemangiomatosis reported in English literature from 1970 to present.

Principles and Applications of Rabbit Models for Atherosclerosis Research

Rabbits are one of the most used experimental animals for biomedical research, particularly as a bioreactor for the production of antibodies. However, many unique features of the rabbit have also made it as an excellent species for examining a number of aspects of human diseases such as atherosclerosis. Rabbits are phylogenetically closer to humans than rodents, in addition to their relatively proper size, tame disposition, and ease of use and maintenance in the laboratory facility. Due to their short life spans, short gestation periods, high numbers of progeny, low cost (compared with other large animals) and availability of genomics and proteomics, rabbits usually serve to bridge the gap between smaller rodents (mice and rats) and larger animals, such as dogs, pigs and monkeys, and play an important role in many translational research activities such as pre-clinical testing of drugs and diagnostic methods for patients. The principle of using rabbits rather than other animals as an experimental model is very simple: rabbits should be used for research, such as translational research, that is difficult to accomplish with other species. Recently, rabbit genome sequencing and transcriptomic profiling of atherosclerosis have been successfully completed, which has paved a new way for researchers to use this model in the future. In this review, we provide an overview of the recent progress using rabbits with specific reference to their usefulness for studying human atherosclerosis.

Recent advances in the pathobiology and management of Kasabach-Merritt phenomenon

Kasabach-Merritt Phenomenon (KMP) refers to the clinical constellation of thrombocytopenia, consumptive coagulopathy and purpura associated with Kaposiform haemangioedothelioma or tufted angioma, but not the more common infantile haemangioma. It shows a variable and unpredictable response to traditional pharmacological agents, such as steroids, vincristine or interferon alpha 2a or 2b. More recently, the interaction between platelets and endothelial cells and the proangiogenic phenotype that results has been recognized to underly the pathogenesis of this disorder. Recent efforts have attempted to target the platelet by using antiplatelet agents and by the withholding of platelet transfusions even in those patients who have significant thrombocytopenia and laboratory evidence of coagulopathy. Excellent response rates and prompt results have been achieved by combining antiplatelet therapy with vincristine, without the need for steroid use. This synergistic approach moves away from the conventional wisdom of treating the underlying lesion to control the coagulopathy. Sirolimus, which is directed against the PI3/AKT/mTOR downstream signalling pathway involved in lymphangiogenesis, has also shown promising results, although further study is needed.

Sclerosed Hemangioma Accompanied by Multiple Cavernous Hemangiomas of the Liver

BACKGROUND

A sclerosed hemangioma of the liver, an extremely rare type of benign hepatic tumor, was found at autopsy.

CASE REPORT

An 81-year-old Japanese man was admitted to our hospital for surgical resection of squamous cell carcinoma of the skin in his left forearm. At admission, serological tests for hepatitis B surface antigen and hepatitis C antibody were negative with no evidence of cirrhosis. At 2, 3, and 5 months after the removal of the forearm tumor, skin grafting was performed because of unhealed skin ulceration. Although anti-bacterial drugs were prescribed, the patient died after the 3rd skin graft (5 months after the surgery) because of pneumonia. During the treatment course, the patient was diagnosed as having multiple liver masses suspected to be cysts of the liver based on non-contrasted computed tomography results. Autopsy revealed a sclerosed hemangioma occupying the entire left lobe accompanied by multiple small cavernous hemangiomas in the right lobe of the liver.

CONCLUSIONS

Sclerosed hemangioma, a rare benign disease, occurred in association with degeneration and sclerosis of cavernous hemangiomas of the liver. The VEGF pathway may be involved in the genesis of cavernous and sclerosed hemangioma of the liver.

Rabbit models for the study of human atherosclerosis: from pathophysiological mechanisms to translational medicine

Laboratory animal models play an important role in the study of human diseases. Using appropriate animals is critical not only for basic research but also for the development of therapeutics and diagnostic tools. Rabbits are widely used for the study of human atherosclerosis. Because rabbits have a unique feature of lipoprotein metabolism (like humans but unlike rodents) and are sensitive to a cholesterol diet, rabbit models have not only provided many insights into the pathogenesis and development of human atherosclerosis but also made a great contribution to translational research. In fact, rabbit was the first animal model used for studying human atherosclerosis, more than a century ago. Currently, three types of rabbit model are commonly used for the study of human atherosclerosis and lipid metabolism: (1) cholesterol-fed rabbits, (2) Watanabe heritable hyperlipidemic rabbits, analogous to human familial hypercholesterolemia due to genetic deficiency of LDL receptors, and (3) genetically modified (transgenic and knock-out) rabbits. Despite their importance, compared with the mouse, the most widely used laboratory animal model nowadays, the use of rabbit models is still limited. In this review, we focus on the features of rabbit lipoprotein metabolism and pathology of atherosclerotic lesions that make it the optimal model for human atherosclerotic disease, especially for the translational medicine. For the sake of clarity, the review is not an attempt to be completely inclusive, but instead attempts to summarize substantial information concisely and provide a guideline for experiments using rabbits.

Hepatic hemangioma in celiac patients: data from a large consecutive series

Background and Aims. Hepatic hemangioma (HH) has a widely ranging prevalence. The etiology is unclear; however, associations with autoimmune disorders have been described. We aimed at evaluating the prevalence of HH in celiac disease. Methods. Ninety-seven consecutive patients with celiac disease (18 M, 79 F, median age 41, and range 17-84 years) underwent liver ultrasound between January 2011 and 2012. The findings were compared with those of 1352 nonceliac patients (581 M, 771 F, median age 50, and range 16-94 years), without liver disease or previously detected HH, who underwent US in the same period. Results. Ultrasonographic findings consistent with HH were observed in 14 celiac patients (14.4%), a prevalence significantly higher than in controls (69 cases, 5.1%) (P = 0.0006). Subgroup analysis showed that, among women, the prevalence of HH was 16.4% in the celiac disease group (13/79) compared with 5.9% in controls (46/771) (P = 0.002). In celiac setting, HH had a median diameter of 1.3 cm and presented as a single lesion in 12 cases (86%). Conclusions. Our findings are consistent with a significantly higher prevalence of HH in celiac patients. Although mechanisms underlying this association remain unclear, autoimmune and metabolic processes, as well as alterations of gut-liver axis equilibrium, could play a role.

Hepatic haemangiomatosis: multinodular liver in an asymptomatic elderly man

A 66-year-old man, overweight and a heavy drinker, was sent to our clinic to investigate multiple liver nodules detected on ultrasound. The patient had no symptoms, and physical examination was unremarkable. Laboratory evaluation disclosed an isolated two-fold increase of γ-glutamyltransferase. The MRI revealed multiple millimetric hypervascular nodules suggestive of liver haemangiomatosis, though malignancy could not be ruled out. Liver biopsy was consistent with hepatic haemangiomatosis. We discuss the differential diagnosis and therapeutical approach of a patient with hepatic haemangiomatosis involving the entire liver without associated symptoms or liver dysfunction.

Tesaglitazar, a dual PPAR-α/γ agonist, hamster carcinogenicity, investigative animal and clinical studies

Tesaglitazar was developed as a dual peroxisome proliferator-activated receptor (PPARα/γ). To support the clinical program, a hamster carcinogenicity study was performed. The only neoplastic findings possibly related to treatment with tesaglitazar were low incidences of hemangioma and hemangiosarcoma in the liver of male animals. A high-power, two-year investigative study with interim necropsies was performed to further elucidate these findings. Treatment with tesaglitazar resulted in changes typical for exaggerated PPARα pharmacology in rodents, such as hepatocellular hypertrophy and hepatocellular carcinoma, but not an increased frequency of hemangiosarcomas. At the highest dose level, there was an increased incidence of sinusoidal dilatation and hemangiomas. No increased endothelial cell (EC) proliferation was detected in vivo, which was confirmed by in vitro administration to ECs. Immunohistochemistry and gene expression analyses indicated increased cellular stress and vascular endothelial growth factor (VEGF) expression in the liver, which may have contributed to the sinusoidal dilatation. A two-fold increase in the level of circulating VEGF was detected in the hamster at all dose levels, whereas no effect on VEGF was observed in patients treated with tesaglitazar. In conclusion, investigations have demonstrated that tesaglitazar does not produce hemangiosarcomas in hamster despite a slight effect on vascular morphology in the liver.

Effects of high-AGE beverage on RAGE and VEGF expressions in the liver and kidneys

BACKGROUND

The formation and accumulation of advanced glycation end products (AGEs) increase in some lifestyle-related diseases as well as in aging; however, little is known about the relationship between food-derived AGEs and the pathology of such diseases.

AIM OF THE STUDY AND METHODS

To explore whether food items containing high levels of AGEs are involved in the development of lifestyle-related diseases, rats were orally administered a commercial high-AGE beverage [Lactobacillus beverage-A (LB-A)]. With a particular focus on angiogenesis-associated diseases, the gene expressions of vascular endothelial growth factor (VEGF) and the receptor for AGEs (RAGE) were examined in the liver and kidneys using real-time reverse transcription-polymerase chain reaction. Moreover, AGE deposition was immunohistochemically investigated in these tissues.

RESULTS AND CONCLUSIONS

Hepatic VEGF expression was significantly increased in rats administered LB-A (P < 0.01 vs. control). Furthermore, immunohistochemical analysis detected glucose-derived AGE-positive cells in the liver from the LB-A group. These results suggest that AGE-rich beverages increase hepatic VEGF expression and AGE accumulation, bringing about early events associated with lifestyle-related diseases.

Intramyocardial injection of autologous bone marrow cells as an adjunctive therapy to incomplete myocardial revascularization--safety issues

OBJECTIVES

To determine the safety of intramyocardial injection of autologous bone marrow cells in patients undergoing surgical myocardial revascularization (CABG) for severe coronary artery disease.

INTRODUCTION

There is little data available regarding the safety profile of autologous bone marrow cells injected during surgical myocardial revascularization. Potential risks include arrythmias, fibrosis in the injected sites and growth of non-cardiac tissues.

METHODS

Ten patients (eight men) were enrolled; they were 59+/-5 years old with limiting angina and were non-optimal candidates for complete CABG. Bone marrow cells (1.3+/-0.3x10(8)) were obtained prior to surgery, and the lymphomonocytic fraction (CD34+ =1.8+/-0.3%) was separated by density gradient centrifugation. During surgery, bone marrow cells were injected in non-grafted areas of ischemic myocardium. During the first year after surgery, the patients underwent laboratory tests, cardiac imaging, and 24-hour ECG monitoring.

RESULTS

Injected segments: inferior (n=7), anterior (n=2), septal (n=1), apical (n=1), and lateral (n=1) walls. Except for a transient elevation of C-reactive protein at one month post-surgery (P=0.01), laboratory tests results were within normal ranges; neither complex arrhythmias nor structural abnormalities were detected during follow-up. There was a reduction in functional class of angina from 3.6+/-0.8 (baseline) to 1.2+/-0.4 (one year) (P<0.0001). Also, patients had a significant decrease in the ischemic score assessed by magnetic resonance, not only globally from 0.65+/-0.14 (baseline) to 0.17+/-0.05 (one year) (P=0.002), but also in the injected areas from 1.11+/-0.20 (baseline) to 0.34+/-0.13 (one year) (P=0.0009).

CONCLUSIONS

Intramyocardial injection of bone marrow cells combined with CABG appears to be safe. Theoretical concerns with arrhythmias and/or structural abnormalities after cell therapy were not confirmed in this safety trial.

Proliferation hemangiomas formation through dual mechanism of vascular endothelial growth factor mediated endothelial progenitor cells proliferation and mobilization through matrix metalloproteinases 9

Infantile hemangioma is the most common tumor of infancy and the mechanism leading to proliferation hemangiomas formation is poorly understood and currently no successful treatment modality exists. We hypothesize that EPCs formed during proliferation hemangiomas, as the result of vascular endothelial growth factor (VEGF) stimulation through MMP9, play the major role in the control of cell proliferation and capillary-like vessels production. Accepting the hypothesis to be correct, a therapy that inhibits EPC mobilization and proliferation can be used to prevent the proliferation hemangiomas formation. Current therapies are only partially effective and safe because they could not eliminate all the relative factors of proliferation hemangiomas formation at all, such as: EPCs in the peripheral blood, and at the same time inducing death (apoptosis and necrosis) of other normal cells. A more efficient prevention of proliferation hemangiomas could be achieved using specific drugs or biologic methods that inhibit EPC mobilization and proliferation. Therapy based on gene therapy, capable to specifically inhibit VEGF and MMP9 expression in gene level, can be possibly effective.

A novel in vivo model of human hemangioma: xenograft of human hemangioma tissue on nude mice

BACKGROUND

Experimental models of human infantile hemangiomas are needed, although none of the current ones is ideal in representing the natural development of hemangioma. In this article, the authors present a nude mice model of human hemangioma with serial morphologic findings on grafts.

METHODS

A specimen of rapidly growing hemangioma tissue was obtained surgically from a 2-month-old boy and was cut into 96 pieces, which were implanted subcutaneously into nude mice, six pieces each. During the 6-month experimental period, gross view, hematoxylin and eosin staining, double immunofluorescent labeling with mouse antihuman CD31 and fluorescein isothiocyanate-labeled rat antimouse CD34, and transmission electron microscopic observation were performed.

RESULTS

Eighty-one of the 96 grafts (84.4 percent) survived and grew during the second month to 3 to 4 months after transplantation, followed by gradual involution. Histologic examination showed cellular edema, degeneration, and necrosis in the early stage. From approximately 30 days, cellular density increased and karyokinesis was identified at 45 days. At 2 months, the grafts were composed mainly of hemangioma tissue and signs of involution appeared. Thereafter, signs of involution turned significant and the grafts were replaced with fibrofatty tissue. It was confirmed through double immunofluorescent labeling that the chief cellular components were endothelial cells of human origin. Findings on ultrastructural investigation were concordant with those on light microscopic observation.

CONCLUSIONS

With human hemangioma tissue implanted into nude mice, an animal model was established successfully. The development of grafts after ischemia resembled the natural course of human infantile hemangioma.

Increased Expression of Vascular Endothelial Growth Factor in Kidney Leads to Progressive Impairment of Glomerular Functions

Vascular endothelial growth factor (VEGF) is an important mediator in maintaining normal kidney functions. In addition, several lines of evidence suggest that upregulation of VEGF in glomeruli may be associated with or cause renal dysfunction such as diabetic nephropathy. For elucidation of the pathologic consequences of high levels of VEGF in glomeruli, transgenic (Tg) rabbits that express human VEGF(165) isoform in both kidney and liver under the control of the human alpha-1-antitrypsin promoter were generated and characterized. With the use of heterozygous Tg rabbits and their littermates aged 8 to 55 wk, renal functions and structures were investigated. Compared with control rabbits, Tg rabbits exhibited progressive proteinuria with increased GFR at the early stage and decreased GFR at the later stage. Histologic examinations revealed that Tg rabbit kidneys were characterized by considerable glomerular hypertrophy as a result of increased proliferation of both glomerular capillaries and mesangial cells accompanied by prominent podocyte hypertrophy. With increasing age starting from 20 wk, Tg rabbit kidneys showed prominent formation of microaneurysms and capillary proliferation at the vascular pole area. At a later stage (55 wk), many glomeruli showed sclerosis and tuft collapse with the formation of glomerular cysts on a background of tubular atrophy and interstitial fibrosis. This study provides the first evidence that increased expression of VEGF in glomeruli directly causes the glomerular hypertrophy that is associated with proteinuria, suggesting that VEGF exerts multiple effects on the glomerular pathophysiologic processes.

Fertility of spermatozoa cryopreserved with 2% acetamide or glycerol through artificial insemination in the Japanese white rabbit

The rabbit is considered to be a valuable laboratory animal. We compared 2% acetamide and glycerol as cryoprotectants in egg-yolk diluent for ejaculated Japanese white rabbit spermatozoa to improve sperm cryopreservation methods. Fertility through artificial insemination, forward progressive motility and plasma membrane integrity of the post-thaw spermatozoa were examined. The rates of forward progressive motility and plasma membrane integrity of the spermatozoa frozen with acetamide (27.1 +/- 8.3% and 24.5 +/- 6.5%) were significantly (P < 0.05) higher than those of the spermatozoa frozen with glycerol (16.3 +/- 10.9% and 14.3 +/- 7.6%). Though there was no significant difference in the kindling rates, the litter size of females inseminated with spermatozoa frozen with acetamide (6.0 +/- 1.1) were significantly (P < 0.05) higher than those of spermatozoa frozen with glycerol (3.0 +/- 0.4). The results indicate that 2% acetamide has a higher cryoprotective effect than 2% glycerol for sperm cryopreservation in the Japanese white rabbit.

Overexpression of Notch1 ectodomain in myeloid cells induces vascular malformations through a paracrine pathway

We previously reported that truncation of Notch1 (N1) by provirus insertion leads to overexpression of both the intracellular (N1(IC)) and the extracellular (N1(EC)) domains. We produced transgenic (Tg) mice expressing N1(EC) in T cells and in cells of the myeloid lineage under the regulation of the CD4 gene. These CD4C/N1(EC) Tg mice developed vascular disease, predominantly in the liver: superficial distorted vessels, cavernae, lower branching of parenchymal vessels, capillarized sinusoids, and aberrant smooth muscle/endothelial cell topography. The disease developed in lethally irradiated normal mice transplanted with Tg bone marrow or fetal liver cells as well as in Rag-/- Tg mice. In nude mice transplanted with fetal liver cells from (ROSA26 x CD4C/N1(EC)) F1 Tg mice, abnormal vessels were of recipient origin. Transplantation of Tg peritoneal macrophages into normal recipients also induced abnormal vessels. These Tg macrophages showed impaired functions, and their conditioned medium inhibited the proliferation of liver sinusoid endothelial cells in vitro. The Egr-1 gene and some of its targets (Jag1, FIII, FXIII-A, MCP-1, and MCP-5), previously implicated in hemangioma or vascular malformations, were overexpressed in Tg macrophages. These results show that myeloid cells can be reprogrammed by N1(EC) to induce vascular malformations through a paracrine pathway.

Comparison of Glycerol, Lactamide, Acetamide and Dimethylsulfoxide as Cryoprotectants of Japanese White Rabbit Spermatozoa

The rabbit is considered to be a valuable laboratory animal. We compared glycerol, lactamide, acetamide, and dimethylsulfoxide (DMSO) as cryoprotectants in egg-yolk diluent of ejaculated Japanese white rabbit spermatozoa for improvement of sperm cryopreservation methods. Rabbit semen was frozen with 1.0 M glycerol, lactamide, acetamide, or DMSO in plastic straws. Forward progressive motility and plasma membrane integrity of the post-thaw spermatozoa were examined. The rate of forward progressive motile spermatozoa in lactamide (37.8 +/- 3.0%) was significantly (P<0.05) higher than in glycerol (17.0 +/- 3.3%). In addition, the rates of sperm plasma membrane integrity in lactamide and acetamide (35.9 +/- 3.3% and 30.2 +/- 3.0%, respectively) were significantly (P<0.05) higher than in glycerol (17.0 +/- 2.6%). The results indicate that 1.0 M lactamide and acetamide have higher cryoprotective effects than 1.0 M glycerol for cryopreservation of Japanese white rabbit spermatozoa.